US11521868B2 - Support plate for localized heating in thermal processing systems - Google Patents

Abstract

Support plates for localized heating in thermal processing systems to uniformly heat workpieces are provided. In one example implementation, localized heating is achieved by modifying a heat transmittance of a support plate such that one or more portions of the support plate proximate the areas that cause cold spots transmit more heat than the rest of the support plate. For example, the one or more portions (e.g., areas proximate to one or more support pins) of the support plate have a higher heat transmittance (e.g., a higher optical transmission) than the rest of the support plate. In another example implementation, localized heating is achieved by heating a workpiece via a coherent light source through a transmissive support structure (e.g., one or more support pins, or a ring support) in addition to heating the workpiece globally by light from heat sources.

Description

PRIORITY CLAIM

The present application claims the benefit of priority of U.S. Provisional Application Ser. No. 62/645,476, titled “SUPPORT PLATE FOR LOCALIZED HEATING IN THERMAL PROCESSING SYSTEMS,” filed on Mar. 20, 2018, the entirety of which is incorporated herein by reference for all purposes.

FIELD

The present disclosure relates generally to thermal processing systems.

BACKGROUND

A thermal processing chamber as used herein refers to a device that heats workpieces, such as semiconductor wafers. Such devices can include a support plate for supporting one or more semiconductor wafers and an energy source for heating the semiconductor wafers, such as heating lamps, lasers, or other heat sources. During heat treatment, the semiconductor wafers can be heated under controlled conditions according to a preset temperature regime.

Many semiconductor heating processes require a wafer to be heated to high temperatures so that various chemical and physical transformations can take place as the wafer is fabricated into a device(s). During rapid thermal processing, for instance, semiconductor wafers can be heated by an array of lamps through the support plate to temperatures from about 300° C. to about 1,200° C., for times that are typically less than a few minutes. During these processes, a primary goal can be to heat the wafers as uniformly as possible.

SUMMARY

Aspects and advantages of embodiments of the present disclosure will be set forth in part in the following description, or may be learned from the description, or may be learned through practice of the embodiments.

One example aspect of the present disclosure is directed to a thermal processing apparatus. The apparatus includes a plurality of heat sources configured to heat a workpiece. The apparatus includes a rotatable support plate operable to support the workpiece during thermal processing. The rotatable support plate includes a transmissive support structure configured to contact the workpiece. The transmissive support structure includes a first end and a second end. The first end of the support structure is arranged to support the workpiece. The apparatus includes a light source operable to emit coherent light through the transmissive support structure such that the coherent light heats a portion of the workpiece contacting the transmissive support structure.

Other example aspects of the present disclosure are directed to systems, methods, devices, and processes for thermally treating a semiconductor substrate.

These and other features, aspects and advantages of various embodiments will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the related principles.

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed discussion of embodiments directed to one of ordinary skill in the art are set forth in the specification, which makes reference to the appended figures, in which:

FIG.1 depicts an example rapid thermal processing (RTP) system having a support plate with spatially arranged low transmission zones according to example embodiments of the present disclosure;

FIGS.2A and2B depict an example support plate with spatially arranged low transmission zones according to example embodiments of the present disclosure;

FIG.3 depicts a flow diagram of a process for heating a workpiece through a support plate with spatially arranged low transmission zones according to example embodiments of the present disclosure;

FIG.4 depicts an example RTP system with a rotatable support plate and a coherent light source according to example embodiments of the present disclosure;

FIG.5 depicts an example base with spatially arranged low transmission zones according to example embodiments of the present disclosure;

FIG.6 depicts an example of coherent light heating a workpiece through a rotatable support plate with spatially arranged low transmission zones according to example embodiments of the present disclosure;

FIG.7 depicts an example rotatable support plate with a ring support according to example embodiments of the present disclosure; and

FIG.8 depicts a flow diagram of a process for heating a workpiece based on a rotatable support plate and a coherent light source according to example embodiments of the present disclosure.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the embodiments, not limitation of the present disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments without departing from the scope or spirit of the present disclosure. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that aspects of the present disclosure cover such modifications and variations.

Example aspects of the present disclosure are directed to support plates for localized heating in thermal processing systems to uniformly heat workpieces, such as semiconductor workpieces, opto-electronic workpieces, flat panel displays, or other suitable workpieces. The workpiece materials can include, for instance, silicon, silicon germanium, glass, plastic, or other suitable material. In some embodiments, the workpieces can be semiconductor wafers. The support plates can be used to support workpieces in various thermal processing systems that implement a variety of workpiece manufacturing processes, including, but not limited to vacuum anneal processes, rapid thermal processes, etc. The support plates can be applied to the above thermal processing systems where one side (e.g., a backside) or both sides of the workpiece are exposed to one or more heat sources.

A thermal processing chamber can include a heat source to emit light ranging from an ultraviolet to a near infrared electromagnetic spectrum. In order to expose one side or both sides of a workpiece to the heat source, the workpiece is supported by one or more support pins mounted onto a carrier structure, typically a base below the workpiece. The support pins and the base form a support plate. In some configurations, the base is made from a highly transparent, uniform material (e.g., quartz glass) as to not obstruct light from the heat sources. However, obstruction of light by the support pins cannot be avoided. As such, there can be a pin spot effect reducing the workpiece temperature at contact areas of the workpiece in contact with the support pins.

During heating the workpiece, the workpiece is not in thermal equilibrium with walls and the support plate in the thermal processing chamber. Even though a thermal conduction of a material (e.g., a quartz material) of a support pin is low and a contact area of the workpiece in contact with the support pin is small, there is still a cooling effect by the thermal conduction into the colder contact area associated with the support pin. Additionally, in fast thermal transients (e.g., rapid thermal processing applications), added thermal mass of a support pin can cause a reduced heat up rate of the workpiece at the contact area. As a result, the workpiece temperature is reduced at the contact area forming a cold spot. Typically, one or more cold spots can be left at one or more contact areas of the workpiece in contact with the support plate. The cold spots can be caused by three main effects, such as shadowing, thermal conduction and higher thermal mass. According to example aspects of the present disclosure, localized heating of the contact areas can be used to compensate the cold spots left on the workpiece.

An example aspect of the present disclosure is directed to a support plate for localized heating in a thermal processing system to compensate cold spots on a workpiece. Localized heating is achieved by modifying a heat transmittance of a support plate such that one or more portions of the support plate proximate the areas that cause cold spots transmit more heat than the rest of the support plate.

For example, the support plate can include a base and one or more support pins for contacting a workpiece during processing. One or more heat sources (e.g., lamp, laser, or other heat sources) are used to heat the workpiece. Localized heating is achieved by modifying an optical transmittance of the support plate such that the areas of the support plate proximate (e.g., under and/or around, above and/or around, etc.) to the support pins transmit more light from the heat sources than the rest of the support plate. For example, the optical transmittance of the support plate is modified such that only portions of the base where the support pins are joined to the base are unchanged with respect to untreated material (e.g., quartz glass) of the base. In portions of the base away from the support pins, the optical transmittance is reduced by treatment of the quartz glass of the base. The treatment to reduce the optical transmittance can include grinding, coating, engraving, or doping. The portions of the base with untreated quartz glass transmit a higher heating flux relative to the portions of the base with treated quartz glass. As such, the workpiece is exposed to a higher heating flux from the portions of the base located proximate to the support pins, resulting in a compensation of cold spots caused by the support pins.

Another example aspect of the present disclosure is directed to a thermal processing apparatus for localized heating in thermal processing systems to compensate cold spots on the workpiece. The thermal processing apparatus includes one or more heat sources (e.g., lamps, or any other heat sources), a coherent light source (e.g., a laser, or any other suitable source), and a rotatable support plate having a support structure (e.g., one or more support pins, or a ring support, etc.). Cold spots resulting from contact of the workpiece with the support structure can be compensated by heating the workpiece via the coherent light source through the support structure in addition to heating the workpiece globally by light from the heat sources. As such, the cold spots are heated locally by light from the coherent light source.

For example, in some embodiments, a cold spot is compensated by shining a beam of the coherent light (e.g., a laser beam) from the coherent light source onto a support pin. The support pin is made from a transmissive material, such as quartz. The coherent light passes through the transmissive support pin to heat the portion of the workpiece contacting the support pin.

In some embodiments, the coherent light source is mounted to a stationary part of the thermal processing apparatus such that the support pin is rotating through the coherent light during rotation of the support plate. The coherent light source, in some embodiments, can be controlled to be switched on and off synchronized to the workpiece rotation as to only heat a contact area of the workpiece in contact with the support pin. For instance, the coherent light source can be controlled only to emit coherent light when the support pin passes in front of the coherent light source during rotation of the support plate.

In some embodiment, the synchronization can be accomplished by shaping the power of the coherent light emitted from the light source. For instance, the power of the coherent light can be controlled to be at a first value when the support pin is not passing in front of the coherent light source. As the support pin approaches the coherent light source, the power of the coherent light can be increased. When the support pin passes through the coherent light source, the power of the coherent light can be controlled to be at a second value that is greater than the first value. As the support pin rotates away from the coherent light source, the power of the coherent light can be decreased, for instance, back to the first value or to a third value that is less than the second value.

In some embodiments, this synchronization can be accomplished by an electrical control circuit, where a trigger signal is generated from a sensor signal indicative of a rotation orientation and a rotation speed. For example, based on known information of the rotation orientation and the speed of the rotatable support plate or of the workpiece, an emission of the coherent light source can be synchronized with a motion of the rotatable support plate. The coherent light source emits coherent light into the support pin and onto the workpiece when the support pin passes over the coherent light source during rotation of the support plate, and the coherent light source stops emitting the coherent light when the support pin is not located in front of the coherent light source.

In some embodiments, localized heating can be achieved by modifying an optical transmission of the base such that one or more portions of the base that are proximate to the support pins transmit the coherent light and the rest of the base is opaque to the coherent light from the coherent light source. The opaque portions of the base can be generated by grinding, coating, engraving, or doping. The opaque portions of the base can be small as to not obstruct light from the heat sources. In some embodiments, an opaque portion is a wavelength selective coating on one side (e.g., a backside) or both sides of the base in form of a semi-annular opaque portion (e.g., a segmented ring). The semi-annular opaque portions can extend between support pins along a path of coherent light along the base during rotation of the support plate relative to the coherent light source.

In some embodiments. a width of the semi-annual opaque portion can be less than or equal to a diameter of a contact area of the coherent light in contact with the base. Examples of the contract area include a focal point of the coherent light onto the base, or a cross-section of the coherent light in contact with the base. The wavelength sensitive coating is selected such that only a narrow band of the coherent light radiation is blocked, whereas a broad band light from the heat sources is almost completely transmitted, reducing an effect on a global temperature uniformity. As such, the synchronization of the coherent light source to the rotatable support plate's rotation is inherently brought about by the rotatable support plate itself. In this example embodiment, the coherent light source can remain on and emit coherent light during an entire heat cycle or relevant portions of the heat cycle.

In some embodiments, the support plate can include a ring support. The ring support can be a transmissive material (e.g., quartz) that allows the passage of coherent light from the coherent light source to heat the workpiece. In this example embodiment, the coherent light source can remain on and emit coherent light during an entire heat cycle or relevant portions of the heat cycle. The ring support can be mounted to the base centered with respect to a center of the workpiece. A height of the ring support can be approximately the same as a height of a support pin. Without additional heating, the ring support can cause a rotational symmetric cold pattern on the workpiece. By placing the coherent light source proximate to (e.g., below) the ring support, and by rotating the workpiece and the ring support about its common center, the cold pattern is compensated by a continuously emitting coherent light from the coherent light source through the ring support onto the workpiece.

Aspects of the present disclosure can achieve a number of technical effects and benefits. For instance, aspects of the present disclosure can reduce the presence of cold spots associated with support pins in thermal processing tools.

Variations and modifications can be made to these example embodiments of the present disclosure. As used in the specification, the singular forms “a,” “and,” and “the” include plural referents unless the context clearly dictates otherwise. The use of “first,” “second,” “third,” and “fourth” are used as identifiers and are directed to an order of processing. Example aspects may be discussed with reference to a “substrate,” “wafer,” or “workpiece” for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that example aspects of the present disclosure can be used with any suitable workpiece. The use of the term “about” in conjunction with a numerical value refers to within 20% of the stated numerical value.

With reference now to the FIGS., example embodiments of the present disclosure will now be discussed in detail.FIG.1 depicts an example rapid thermal processing (RTP)system100 having asupport plate120 with spatially arranged low transmission zones according to example embodiments of the present disclosure. As illustrated, theRTP system100 includes aRTP chamber105, aworkpiece110, asupport plate120,heat sources130 and140,air bearings145, apyrometer165, acontroller175, adoor180, and agas flow controller185.

Theworkpiece110 to be processed is supported in the RTP chamber105 (e.g., a quartz RTP chamber) by thesupport plate120. Thesupport plate120 supports theworkpiece110 during thermal processing. Thesupport plate120 includes arotatable base135 and at least onesupport structure115 extending from therotatable base135. A support structure describes a structure contacting and supporting a workpiece during thermal processing. Examples of the support structure can include one or more support pins, a ring support, or any other suitable support that contacts and supports a workpiece. As shown inFIG.1, thesupport structure115 includes one or more support pins (only one shown). Thesupport structure115 and therotatable base135 can transmit heat from theheat sources140 and to absorb heat from theworkpiece110. In some embodiments, thesupport structure115 and therotatable base135 can be made of quartz. Therotatable base135 rotates theworkpiece110 at a defined rotation orientation and at a defined rotation speed, as further described below.

A guard ring (not shown) can be used to lessen edge effects of radiation from one or more edges of theworkpiece110. Anend plate190 seals to thechamber105, and thedoor180 allows entry of theworkpiece110 and, when closed, allows thechamber105 to be sealed and aprocess gas125 to be introduced into thechamber105. Two banks of heat sources (e.g., lamps, or other suitable heat sources)130 and140 are shown on either side of theworkpiece110. The controller175 (e.g., a computer, microcontroller(s), other control device(s), etc.) is used to control theheat sources130 and140. Thecontroller175 can be used to control thegas flow controller185, thedoor180, and/or the temperature measuring system, denoted here as thepyrometer165.

Agas flow150 can be an inert gas that does not react with theworkpiece110, or thegas flow150 can be a reactive gas such as oxygen or nitrogen that reacts with the material of the workpiece110 (e.g. a semiconductor wafer, etc.) to form a layer of on theworkpiece110. Thegas flow150 can be a gas that can contain a silicon compound that reacts at a heated surface of theworkpiece110 being processed to form a layer on the heated surface without consuming any material from the surface of theworkpiece110. When thegas flow150 reacts to form a layer on the surface, the process is called rapid thermal-chemical vapor deposition (RT-CVD). In some embodiments, an electrical current can be run through the atmosphere in theRTP system100 to produce ions that are reactive with or at the surface, and to impart extra energy to the surface by bombarding the surface with energetic ions.

Thecontroller175 controls therotatable base135 to rotate theworkpiece110. For example, thecontroller175 generates an instruction that defines the rotation orientation and the rotation speed of therotatable base135, and controls therotatable base135 to rotate theworkpiece110 with the defined rotation orientation and the defined rotation speed. Therotatable base135 is supported by theair bearings145. Thegas flow150 impinging on therotatable base135 causes therotatable base135 to rotate about anaxis155.

In some embodiments, therotatable base135 can have a first portion associated with a first heat transmittance and a second portion associated with a second heat transmittance. The second heat transmittance is different from the first heat transmittance. The second portion is located proximate to the support pins115. Examples of therotatable base135 are further described below in conjunction withFIGS.2A and2B.

FIGS.2A and2B depict anexample support plate200 with spatially arranged low transmission zones according to example embodiments of the present disclosure. In the embodiments ofFIGS.2A and2B, thesupport plate200 includes threesupport pins210 and arotatable base230. More or fewer support pins can be used without deviating from the scope of the present disclosure.

In some embodiments, thesupport plate200 is an example embodiment of the support plate120 (FIG.1), and onesupport pin210 is an embodiment of example support pin115 (FIG.1). Eachsupport pin210 has afirst end212 and asecond end214. Thefirst end212 of thesupport pin210 contacts and supports a workpiece (not shown). Thesecond end214 of thesupport pin210 contacts (e.g., is coupled to) therotatable base230. In some embodiments, the support pin(s)210 can be integral with therotatable base230.

As shown, therotatable base230 includes threecircular areas220. Eachcircular area220 is located proximate to thesecond end214 of onesupport pin210. A diameter of onecircular area220 is greater than a diameter of a contact area of acorresponding support pin210 contacting therotatable base230. A center of onecircular area220 coincides with a center of acorresponding support pin210. Remainingareas240 of therotatable base230 describe areas that exclude the threecircular areas220 within therotatable base230. The remainingareas240 are associated with a first heat transmittance, and the threecircular areas220 are associated with a second heat transmittance. The second heat transmittance can be different from the first heat transmittance. For example, the second heat transmittance can be higher than the first heat transmittance. Theareas240 are referred to as low transmission zones that have lower heat transmittance than thecircular areas220. As such, thecircular areas220 transmit more heat than the remainingareas240 to compensate cold spots that can be left on the workpiece supported by the support pins210. As a result, more uniform heat is distributed to the workpiece via thesupport plate200.

The present disclosure is discussed withareas220 having a circular shape for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand thatareas220 can have other shapes without deviating from the scope of the present disclosure.

In some embodiments, an optical transmittance of thesupport plate200 is modified such that thecircular areas220 are unchanged with respect to untreated material (e.g., untreated quartz) of therotatable base230. The remaining areas can be treated material (e.g., treated quartz) having a reduced optical transmittance relative to thecircular areas220. The treated quartz can be treated with one or more of grinding, coating, engraving, or doping. Thecircular areas220 with untreated quartz transmit a higher heating flux relative to the remainingareas240 with treated quartz. As such, the workpiece is exposed to a higher heating flux from thecircular areas220, resulting in a compensation of cold spots caused by the support pins210.

Aspects of the present disclosure are discussed with reference to a support plate with one or more support pins as a support structure and with a rotatable base for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that non-rotatable bases can be used without deviating from the scope of the present disclosure. For example, a non-rotatable base can have a first portion associated with a first heat transmittance and a second portion associated with a second heat transmittance. The second heat transmittance is different from the first heat transmittance, and the second portion is located proximate to a support structure (e.g., a support pin, a ring support, etc.). Those of ordinary skill in the art, using the disclosures provided herein, will understand that any support structure (e.g., a support pin, a ring support, a support structure with an arbitrary shape, etc.) can be used without deviating from the scope of the present disclosure

FIG.3 depicts a flow diagram of a process (300) for heating a workpiece through a support plate with spatially arranged low transmission zones according to example embodiments of the present disclosure. The process (300) can be implemented using theRTP system100 ofFIG.1. However, as will be discussed in detail below, the process (300) according to example aspects of the present disclosure can be implemented using other thermal processing systems without deviating from the scope of the present disclosure.FIG.3 depicts steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that various steps of any of the methods described herein can be omitted, expanded, performed simultaneously, rearranged, and/or modified in various ways without deviating from the scope of the present disclosure. In addition, various additional steps (not illustrated) can be performed without deviating from the scope of the present disclosure.

At (310), the process can include placing a workpiece on a support plate in a processing chamber. For example, in the embodiment ofFIG.1, thesupport plate120 includes the support pins115 and therotatable base135. Theworkpiece110 is placed on the support pins115 in theRTP chamber120 via thedoor180. In some embodiments, thesupport plate120 can be used in an anneal processing chamber. For example, a workpiece for annealing can be placed on thesupport plate120 in the anneal processing chamber. In some embodiments, thesupport plate120 can include other support structures (e.g., a ring support, a support structure with an arbitrary shape, etc.). In some embodiments, thesupport plate120 can include a non-rotatable base with spatially arranged low transmission zones.

At (320), the process can include rotating the workpiece with the support plate in the processing chamber. For example, in the embodiment ofFIG.1, thecontroller175 instructs therotatable base135 to rotate theworkpiece110 in theRTP chamber105.

At (330), the process can include heating the workpiece with a plurality of heat sources through the support plate. For example, in the embodiment ofFIG.1, thecontroller175 controls theheat sources140 to heat theworkpiece110 through therotatable base135 and thesupport bins115 to a preset temperature.

At (340), the process can include removing the workpiece from the support plate. For example, in the embodiment ofFIG.1, theworkpiece110 can be removed from thesupport bins115 to exit from theRTP chamber105 via thedoor180.

FIG.4 depicts anexample RTP system400 with arotatable support plate410 and a coherentlight source430 according to example embodiments of the present disclosure. As illustrated, theRTP system400 includes theRTP chamber105, theworkpiece110, therotatable support plate410 having support pins415 and abase420, a coherentlight source430, acontroller440,heat sources130 and140,air bearings145, thepyrometer165, thedoor180, and thegas flow controller185.

The coherent light source430 (e.g., a laser) can providecoherent light435 to thechamber105. In some embodiments, the coherentlight source430 is located external to thechamber105 and transmits light435 to thechamber105 via an optical pipe or light guide432 (e.g., fiber optic).

Therotatable support plate410 supports theworkpiece110 during thermal processing. Therotatable support plate410 includes a transmissive support structure and arotatable base415. The transmissive support structure describes a structure that contacts and supports theworkpiece110, and transmits light435 from the coherent light source430 (e.g., a laser) to theworkpiece110 during thermal processing. Examples of the transmissive support structure can include one or more support pins, a ring support, or any other suitable support that contacts and supports theworkpiece110, and transmits light to theworkpiece110.

The transmissive support structure includes a first end and a second end. The first end of the transmissive support plate is arranged to support theworkpiece110. The second of the transmissive support plate contacts (e.g., is coupled to) a first surface of therotatable base420. In the example embodiment ofFIG.1, the transmissive support structure includes one or more support pins415 (only one shown). One end of onesupport pin415 contacts a backside of theworkpiece110, and the other end of thesupport pin415 contacts a surface of thebase420. Thebase420 rotates theworkpiece110 at a defined rotation orientation and at a defined rotation speed based on an instruction received from thecontroller440, as further described below.

In some embodiments, the transmissive support structure and the base420 can transmit heat from theheat sources140 and to absorb heat from theworkpiece110. For example, the transmissive support structure and the base420 can be made of quartz.

In some embodiments, therotatable support plate410 includes one or more support pins415, and the base420 having a semi-annular opaque portion (shown inFIGS.5 and6) disposed between at least two of the support pins415. The semi-annular opaque portion can obstruct coherent light of the coherentlight source430 from heating theworkpiece110 such that the coherentlight source430 can continuously emit the coherent light into onto the base420 during the rotation of theworkpiece110.

In some embodiments, therotatable support plate410 includes a ring support (shown inFIG.7) and thebase420. For example, both the ring support and the base420 can be a transmissive material (e.g., quartz) that allows the passage of coherent light continuously emitted from the coherentlight source430 to heat theworkpiece110

The coherentlight source430 emitscoherent light435 through therotatable base420 and the transmissive support structure such that the coherent light heats a portion of theworkpiece110 contacting the transmissive support structure. Examples of the coherentlight source430 can include a continuous wave laser, a pulsed laser, or other suitable light source emitting coherent light.

In the example embodiment ofFIG.4, the coherentlight source430 is mounted to a stationary part of theRTP chamber105 such that thesupport pin415 is rotating through thecoherent light435 during rotation of therotatable support plate410. The coherentlight source430 emitscoherent light435 onto a backside of thebase420, and the emitted coherent light can pass through thesupport pin415 to heat a contact area of theworkpiece110 contacting thesupport pin415. As such, a cold spot resulting from contact of theworkpiece110 with thesupport pin415 can be compensated by heating theworkpiece110 via the coherentlight source430 through thesupport pin415 in addition to heating theworkpiece110 globally by light from the heat sources140. In some embodiments, the coherentlight source430 is controlled by thecontroller440 to be switched on and off synchronized to theworkpiece110 rotation as to heat a contact area of the workpiece in contact with thesupport pin415. Thecontroller440 controls one or more of therotatable base415, the coherentlight source430, theheat sources130 and140, thegas flow controller185, thedoor180, and thepyrometer165. Thecontroller440 controls the base420 to rotate theworkpiece110 with a defined rotation orientation and a defined rotation speed. For example, thecontroller440 generates an instruction that defines a rotation orientation and a rotation speed of thebase420, and controls the base420 to rotate theworkpiece110 with the defined rotation orientation and the defined rotation speed. In some embodiments, thecontroller440 controls the coherentlight source430 to emitcoherent light435 based on the rotation orientation and the rotation speed of thebase420. For example, thecontroller440 can include an electrical control circuit that generates a trigger signal to trigger the coherentlight source430 to emitcoherent light435 based on a sensor signal indicative of a rotation orientation and a rotation speed of thebase420.

In some embodiments, thecontroller440 synchronizes an emission of the coherent light from the coherentlight source430 with a motion of the base420 such that the coherentlight source430 emits the coherent light into one of the support pins415 and onto theworkpiece110 when thatsupport pin415 passes over the coherentlight source430 during rotation of thebase420, and such that the coherentlight source430 stops emitting the coherent light when thatsupport pin415 is not located in front of the coherentlight source430. For example, thecontroller440 generates an instruction that instructs the coherentlight source430 to emit coherent light based on a rotation orientation and a rotation speed of thebase420. The instruction can include a command that instructs the coherentlight source430 to emit coherent light, a command that instructs the coherentlight source430 to stop emitting the coherent light, a command that calculates a time interval between an emission and a subsequent emission of the coherentlight source430 based on the rotation orientation and the rotation speed of theworkpiece110, etc.

In some embodiments, thecontroller440 controls the coherentlight source430 to continuously emit the coherent light into the transmissive support structure. For example, thecontroller440 generates an instruction that instructs the coherentlight source430 to remain on and continuously emit the coherent light onto thebase420. The base420 can include a semi-annular opaque portion obstructing coherent light of the coherentlight source430 from heating portions theworkpiece110 not in contact with the support structure. When thesupport pin415 is not located in front of the coherentlight source430, thecontroller440 instructs thecoherent light430 to remain on and to continuously emit coherent light onto the semi-annular opaque portion such that the emitted coherent light is blocked by the semi-annular opaque portion. When thesupport pin415 passes in front of the continuously emitted coherent light, the coherent light passes through thesupport pin415 to heat theworkpiece110.

In another example, thecontroller440 generates an instruction that instructs the coherentlight source430 to remain on and continuously emit the coherent light onto therotatable support plate410 with a ring support. During the rotation of theworkpiece110, the ring support always passes over the coherentlight source430 and transmits the coherent light to heat theworkpiece110. Thecontroller440 instructs the coherentlight source430 to continuously emit the coherent light into the ring support. As such, a cold pattern caused by the ring support is compensated by continuously shining the coherent light from the coherentlight source430 through the ring support ontoworkpiece110.

FIG.5 depicts anexample base500 with spatially arranged low transmission zones according to example embodiments of the present disclosure. In the embodiment ofFIG.5, the base500 can be an embodiment of thebase420. Thebase500 includes three round-shape portions510, multiple semi-annularopaque portions520, and remainingportions530. One round-shape portion510 is a contact area of a workpiece contacting a support pin (not shown). Each semi-annular opaque portion is disposed between any two of the three round-shape portions510. The remainingportions530 of the base500 describe portions that exclude the three round-shape portions510 and multiple semi-annularopaque portions520 within thebase500.

FIG.6 depicts an example ofcoherent light610 heating theworkpiece110 through thebase500 and thesupport pin415 according to example embodiments of the present disclosure. Thecoherent light610 is emitted from a coherent light source (not shown). Thecoherent light610 passes through thesupport pin415 to heat theworkpiece110. When thebase500 rotates, thesupport pin415 is not located in front of thecoherent light610, but one semi-annularopaque portion520 passes over thecoherent light610 and obstructs thecoherent light610 to heat theworkpiece110. As such, cold spots are compensated by shining a continuously emitting coherent light onto each support pin during the rotation of thebase500.

In the embodiment ofFIGS.5 and6, a width of the semi-annularopaque portion520 is not less than a diameter of a contact area of thecoherent light610 in contact with thebase500. Examples of the contract area of thecoherent light610 include a focal point of thecoherent light610 onto thebase500, or a cross-section of thecoherent light610 contacting thebase500. The round-shape portions510 and the remainingportions530 can be unchanged with respect to untreated material (e.g., untreated quartz) of thebase500. The semi-annularopaque portions520 can be treated material (e.g., treated quartz) that obstructs coherent light of a coherent light source (not shown) from heating theworkpiece110. The treated material can be treated with one or more of grinding, coating, engraving, or doping. In some embodiments, the semi-annularopaque portions520 includes a wavelength selective coating on one side (e.g., a backside) or both sides of thebase500. The wavelength sensitive coating is selected such that only a narrow band of the coherent light radiation is blocked, whereas a broad band light from the heat sources is almost completely transmitted, reducing an effect on a global temperature uniformity.

In some embodiments, the semi-annularopaque portions520 can extend between support pins415 along a path ofcoherent light610 along the base500 during rotation of the base500 relative to a coherent light source (not shown). The semi-annularopaque portions520 can be small as to not obstruct light from heat sources (not shown). The semi-annularopaque portions520 are also referred to low transmission zones that obstruct coherent light to heat a workpiece.

Aspects of the present disclosure are discussed with reference to a rotatable support plate with three support pins as transmissive support structures for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that multiple disconnected supports with a rotatable symmetric arrangement can be used without deviating from the scope of the present disclosure. For example, multiple supports are not connected with each other, but these multiple supports are arranged in rotatable symmetric pattern on the base. A support can have an arbitrary shape.

FIG.7 depicts an examplerotatable support plate700 with aring support720 according to example embodiments of the present disclosure. In the embodiment ofFIG.7, therotatable support700 can be an embodiment of therotatable support plate410. Therotatable support700 includes arotatable base710 and thering support720. Thering support720 is centered with respect to a center of therotatable base710. In some embodiments, thering support720 is centered with respect to a center of a workpiece (not shown) contacting thering support720. A width of thering support720 is not less than a diameter of a contact area of the coherent light (not shown) in contact with thering support720. Examples of the contact area of the coherent light include a focal point of the coherent light onto thering support720, or a cross-section of the coherent light contacting thering support720. In some embodiments, a height of thering support710 can be approximately the same as a height of thesupport pin415. In some embodiments, both therotatable base710 and thering support720 can be a transmissive material (e.g., untreated quartz) that allows the passage of coherent light from a coherent light source to heat a workpiece. As such, a coherent light source can continuously emit coherent light that passes through therotatable base710 and thering support720 to heat a workpiece contacting thering support720. Additionally, a cold pattern caused by thering support720 can be compensated by a continuously emission from the coherent light source to heat the workpiece.

Aspects of the present disclosure are discussed with reference to a rotatable support plate with a ring support as a transmissive support structure for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that any transmissive support structure with a rotatable symmetric shape can be used without deviating from the scope of the present disclosure.

FIG.8 depicts a flow diagram of a process (800) for heating a workpiece based on a rotatable support plate and a coherent light source according to example embodiments of the present disclosure. The process (800) can be implemented using theRTP system400. However, as will be discussed in detail below, the process (800) according to example aspects of the present disclosure can be implemented using other thermal processing systems without deviating from the scope of the present disclosure.FIG.8 depicts steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that various steps of any of the methods described herein can be omitted, expanded, performed simultaneously, rearranged, and/or modified in various ways without deviating from the scope of the present disclosure. In addition, various additional steps (not illustrated) can be performed without deviating from the scope of the present disclosure.

At (810), the process can include placing a workpiece on a rotatable support plate in a processing chamber. The rotatable support plate includes a transmissive support structure and a base. For example, in the embodiment ofFIG.4, therotatable support plate410 includes support pins415 and thebase420. Theworkpiece110 is placed on the support pins415 in theRTP chamber105 through thedoor180. In some embodiments, therotatable support plate410 can be used in an anneal processing chamber. For example, a workpiece for annealing can be placed on therotatable support plate410 in the anneal processing chamber.

At (820), the process can include heating the workpiece using one or more heat sources. For example, in the embodiment ofFIG.4, thecontroller440 controls theheat sources140 to heat theworkpiece110 through thebase420 and thesupport bins415 to a preset temperature.

At (830), the process can include rotating the workpiece with the rotatable support plate relative to the one or more heat sources during heating of the workpiece. For example, in the embodiment ofFIG.4, thecontroller440 instructs the base420 to rotate theworkpiece110 in theRTP chamber105 with a defined rotation orientation and a defined rotation speed.

At (840), the process can include emitting coherent light from a coherent light source through the base and the transmissive support structure such that the coherent light heats a portion of the workpiece contacting the transmissive support structure. For example, in the embodiment ofFIG.4, thecontroller440 synchronizes an emission of the coherent light from the coherentlight source430 with a motion of the base420 such that the coherentlight source430 emits the coherent light into one of the support pins415 and onto theworkpiece110 when thatsupport pin415 passes over the coherentlight source430 during rotation of thebase420, and such that the coherentlight source430 stops emitting the coherent light when thatsupport pin415 is not located in front of the coherentlight source430. In another example, thecontroller440 controls the coherentlight source430 to continuously emit the coherent light to heatworkpiece110 through the rotatable support plate410 (e.g., a rotatable support plate withsupport pins415 and the base500 inFIGS.5 and6, or therotatable support plate700 inFIG.7).

At (850), the process can include removing the workpiece from the rotatable support plate. For example, in the embodiment ofFIG.4, theworkpiece110 can be removed from thesupport bins415 to exit from theRTP chamber105 via thedoor180.

Aspects of the present disclosure are discussed with reference to a rotatable support plate. Those of ordinary skill in the art, using the disclosures provided herein, will understand that example aspects of the present disclosure can be implemented with a stationary support plate. For instance, one or more coherent light sources can be positioned in view of a support pin on the stationary support plate. The coherent light source can emit coherent light onto the stationary support plate and through the support pin for cold spot reduction on the workpiece.

While the present subject matter has been described in detail with respect to specific example embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art.

Claims (10)

What is claimed is:

1. A thermal processing apparatus, comprising:

a plurality of heat sources configured to heat a workpiece;

a rotatable support plate operable to support the workpiece during thermal processing, the rotatable support plate comprising:

a transmissive support structure configured to contact the workpiece, the transmissive support structure comprising a first end and a second end, wherein the first end of the transmissive support structure is arranged to support the workpiece; and

a light source operable to emit coherent light through the transmissive support structure such that the coherent light heats a portion of the workpiece contacting the transmissive support structure,

wherein the rotatable support plate comprises a base, the base having semi-annular opaque portions of treated material that are each disposed between transmissive portions of untreated material, wherein one of the transmissive portions of untreated material contacts the second end of the transmissive support structure, wherein the semi-annular opaque portions of treated material are configured to obstruct the coherent light of the light source from heating the workpiece, and wherein the transmissive portions of untreated material are configured to transmit the coherent light of the light source to the transmissive support structure.

2. The thermal processing apparatus ofclaim 1, wherein the transmissive support structure is configured to transmit heat from the plurality of heat sources to the workpiece.

3. The thermal processing apparatus ofclaim 1, wherein the transmissive support structure comprises a quartz material.

4. The thermal processing apparatus ofclaim 1, wherein the light source is configured to be maintained stationary relative to the rotatable support plate during rotation of the rotatable support plate during thermal processing of the workpiece.

5. The thermal processing apparatus ofclaim 1, wherein the light source comprises a laser.

6. The thermal processing apparatus ofclaim 1, wherein the transmissive support structure comprises a plurality of support pins.

7. The thermal processing apparatus ofclaim 6, wherein the semi-annular opaque portions of treated material are each disposed between at least two of the plurality of support pins.

8. The thermal processing apparatus ofclaim 1, wherein a width of each of the semi-annular opaque portions of treated material is not less than a diameter of a contact area of the coherent light in contact with the base.

9. The thermal processing apparatus ofclaim 1, wherein each of the semi-annular opaque portions of treated material comprises a wavelength selective coating on a surface of the base.

10. The thermal processing apparatus ofclaim 1, further comprising a controller configured to synchronize an emission of the coherent light from the light source with a motion of the base such that the light source emits the coherent light into the transmissive support structure and onto the workpiece when the transmissive support structure passes over the light source during rotation of the rotatable support plate, and such that the light source stops emitting the coherent light when the transmissive support structure is not located in front of the light source.

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